30 



Forekomst og Leveyis. 



Den lier omhandlede mærkelige Dyreform fore- 

 kommer ikke sjelden langs vor hele Kyst, fra Chri- 

 stianiafjorden til Vadsø, men synes idethele at op- 

 træde baade hyppigst og kraftigst udviklet i vor 

 arktiske Region. I stor Mængde har jeg saaledes 

 fundet den paa en Plads i Lofoten, Brettesnæs, hvor 

 mange hundrede Individer indsamledes i Lobet af et 

 Par Dage, og ogsaa ved Finmarken har jeg paa sine 

 Steder truffet den i mængdevis. Den pleier at holde 

 til paa maadeligt Dyb, fra 10 til 30 Favne, og helst 

 paa saadanne Steder, hvor Bunden er dækket af 

 forraadnende Tangarter, hvoraf den for en væsent- 

 lig Del synes at ernære sig. Ligesom Tilfældet er 

 med flere andre Crustaceer, synes Hannerne kun til 

 visse bestemte Tider af Aaret at opnaa fuld Slaegts- 

 modenhed, og optræder da kun ganske enkeltvis. Der- 

 imod er endmi ikke slægtsmodent iidviklede Hanner 

 at finde til enhver Tid af Aaret og næsten i samme 

 Antal som Hunnerne. I Maaden at bevæge sig paa, 

 ligesom i sin hele ydre Habitus, har dette Dyr en 

 umiskjendelig Lighed med en colossal Copepode; 

 navnlig er den habituelle Overensstemmelse med 

 visse Harpacticider meget paafaldende. Ligesom hos 

 disse sidste, er Legemet overordentlig boieligt, navn- 

 lig i dorsal Retning, og kan ofte krummes saa stærkt, 

 at Halegrenene kommer i Contact med Pandepladen. 

 Bevægelsen sker stedvis ved kraftige og temmelig 

 rythmiske Slag af Svømmefødderne, hvorved Lege- 

 met drives frem med temmelig betydelig Fart. De 

 slægtsmodne Hanner er overotdentlig raske i sine 

 Bevægelser og foretager ofte længere Udflugter i 

 Våndet. Derimod holder Hunnerne og de endnu ikke 

 fuldt udviklede Hanner sig i Regelen ved Bunden 

 og bevæger sig her mellem Bundmaterialet, ialmin- 

 delighed paa Siden. De forstaar herunder med stor 

 Behændighed at skjule sig mellem Mudret eller de 

 hensmuldrende Tangrester, som bedækker samme, 

 saa det slet ikke er saa let at finde dem frem, trods 

 den ikke ubetydelige Størrelse. Lettest opdager 

 man dem ved at slaa det optagne Bundraateriale ud 

 i et fladt Kar, med en ubetydelig Kvantitet af Sjø- 

 vand. De tilstedeværende Exemplarer vil da, især 

 naar man rører lidt om i Bundsatsen, snart vise sig 

 paa Overfladen af Våndet, og da de i Lighed med 

 forskjellige andre Crustaceer ikke formaar at komme 

 ned i Våndet igjen, etterat de forst er komne i Be- 

 rorelse med Luften, kan de med Lethed opsamles i 

 levende Tilstand. Bringer man et helst yngre Li- 

 divid i en passende Kvantitet Sjøvand under Mikro- 

 skopet, kan man saa noiere studere de forskjellige 

 Livsytringer og kan gjennem de halvt gjennemsigtige 

 Integi;menter observere Hjertets Pulsationer, Tar- 

 mens perestaltiske Bevægelser og Branchialfoddernes 

 Spil. Disse sidste, der ingensomhelst Inflydelse har 

 paa Locomotionen, vil man i Regelen finde i en 



Distributiou and L åbits. 



The remarkable animal form spoken of here 

 appears not rarely along our entire coast, from the 

 Christianiafiord to Vadsø, but seems, on the whole, 

 to appear most frequently, and most powerfully de- 

 veloped in our Arctic region. I have thus found it 

 in great abundance at a place, Brettesnæs in Lo- 

 foten, where many hiindreds of individuals were col- 

 lected in the course of a couple of days; and also 

 in Finmark I have, in certain places, met with it 

 in great abundance. It is accustomed to keep itself 

 at a moderate depth, from 10 to 30 fathoms, and 

 preferably in those places where the bottom is co- 

 vered with decomposing sea-weed of which it appears, 

 to a material extent, to nourish itself. Like what 

 is the case with several other Crustaceans, the males 

 appear to only attain full power of reproduction at 

 certain fixed seasons of the year, and are then met 

 with only quite solitary. On the other hand, not 

 fully reproductively ripe developed males are to be 

 found at all seasons of the year, and almost in 

 equal number to the females. In manner of 

 movement, as well as in entire external habitus 

 this animal has an unmistakable likeness to a 

 colossal Copepod, especially is the habitual agree- 

 ment with certain Harpacticidæ very striking. Like 

 as in those last, the body is extraordinarily flexible, 

 especially in dorsal direction, and may ofen be so 

 strongly bent that the caudal branches come into 

 contact with the frontal plate. The movement takes 

 place in jerks, w^ith povvcrful and tolerably ryth- 

 mical strokes of the swimming feet, by which the 

 body is drawn forwards with pretty considerable 

 speed. The reproductively ripe males are extra- 

 ordinarily active in their movements, and frequently 

 make long excursions in the water. On the other 

 hand, the females and the not yet fully developed 

 males remain, as a rule, at the bottom, and move 

 here among the material of the bottom, generally 

 on the side. In doing this they understand to con- 

 ceal themselves with great dexterity in the mud, or 

 the decomposing remains of sea-weed which covers 

 it, so that it is not at all ea.sy to search them out, 

 in spite of the not inconsiderable size. We find 

 them easiest by pouring the collected bottom mate- 

 rial into a flat vessel, along with an inconsiderable 

 quantity of sea-water. The specimens present will 

 then, especially if the bottom stuff is stirred a little 

 up, soon show themselves on the surface of the 

 water, and as they, like several other Crustaceans, 

 are unable to swim downwax'ds in the water again 

 after they have first come into contact with the air, 

 they may with ease be collected in the live state. 

 If we place, preferably a young individual, in a 

 suitable quantity of sea-water, under the microscope, 

 we can then more closely study the varioiis features 



